Discrete unified gas-kinetic wave-particle method for flows in all flow regimes

Area of Science:

• Computational Fluid Dynamics
• Kinetic Theory

Background:

• Simulating fluid flows across all regimes (rarefied to continuum) presents significant computational challenges.
• Existing methods like Discrete Velocity Method (DVM) and Direct Simulation Monte Carlo (DSMC) have limitations in scope or efficiency.

Purpose of the Study:

• To introduce a novel computational method, the Discrete Unified Gas-Kinetic Wave-Particle (DUGKWP) method.
• To develop a unified approach capable of accurately simulating fluid flows in all flow regimes.

Main Methods:

• The DUGKWP method integrates microscopic particle information with macroscopic flow variables.
• Microscopic particles are updated via free-transport and resampling.
• Macroscopic flow properties are solved using the finite volume method applied to conservation laws.
• The method utilizes a discrete characteristic solution to the Boltzmann-BGK equation.

Main Results:

• The DUGKWP method accurately predicts flow properties across all flow regimes, from rarefied to continuum.
• In rarefied flows, microscopic particle motion significantly influences macroscopic fluxes.
• In continuum flows, the DUGKWP method effectively reduces to a Navier-Stokes solver.
• The DUGKWP method demonstrates superior computational efficiency and reduced memory consumption compared to deterministic methods.

Conclusions:

• The DUGKWP method provides a unified and efficient framework for simulating fluid dynamics across all flow regimes.
• This approach offers a significant advancement in computational fluid dynamics, particularly for high-speed rarefied and near-continuum flows.